Method for producing chemically modified cellulose fiber

Abstract

Provided is a method for producing a chemically modified cellulose fiber with which fibrillation can be performed along with sulfation reaction.The method for producing a chemically modified cellulose fiber includes a step (a) of treating a cellulose fiber with sulfamic acid to allow a cellulose fine fiber which is a constituent of the cellulose fiber to react with the sulfamic acid, thereby substituting some of hydroxyl groups of cellulose with a substituent represented by a structural formula (1) below (where M represents a monovalent to trivalent cation), and a step (b) of performing fibrillation simultaneously with the step (a).

The invention claimed is: 
     
       1. A method for producing a chemically modified cellulose fiber, comprising:
 treating a cellulose fiber with sulfamic acid such that a cellulose fine fiber which is a constituent of the cellulose fiber is allowed to react with the sulfamic acid and that some of hydroxyl groups of cellulose is substituted with a substituent of formula (1) 
 
       
         
           
           
               
               
           
         
       
       where M is a monovalent to trivalent cation; and
 performing fibrillation simultaneously with the treating of the cellulose fiber with the sulfamic acid. 
 
     
     
       2. The method of  claim 1 , wherein the treating of cellulose fiber with the sulfamic acid comprises treating the cellulose fiber having an average degree of polymerization of less than 350 with the sulfamic acid. 
     
     
       3. The method of  claim 1 , wherein the chemically modified cellulose fiber has a cellulose I crystal structure and the substituent substituting some of hydroxyl groups of cellulose in the chemically modified cellulose fiber such that an amount of the substituent is in a range of 0.1 to 3.0 mmol per 1 g of the chemically modified cellulose fiber, and the chemically modified cellulose fiber has an average degree of polymerization of less than 350. 
     
     
       4. The method of  claim 2 , wherein the chemically modified cellulose fiber has a cellulose I crystal structure and the substituent substituting some of hydroxyl groups of cellulose in the chemically modified cellulose fiber such that an amount of the substituent is in a range of 0.1 to 3.0 mmol per 1 g of the chemically modified cellulose fiber, and the chemically modified cellulose fiber has an average degree of polymerization of less than 350. 
     
     
       5. The method of  claim 1 , wherein the treating of cellulose fiber with the sulfamic acid comprises treating the cellulose fiber having an average degree of polymerization of less than 320 with the sulfamic acid. 
     
     
       6. The method of  claim 1 , wherein the treating of cellulose fiber with the sulfamic acid comprises treating the cellulose fiber having an average degree of polymerization of less than 300 with the sulfamic acid. 
     
     
       7. The method of  claim 1 , wherein the treating of cellulose fiber with the sulfamic acid comprises treating the cellulose fiber having an average degree of polymerization in a range of 100 to 350 with the sulfamic acid. 
     
     
       8. The method of  claim 1 , wherein the treating of cellulose fiber with the sulfamic acid comprises treating the cellulose fiber having an average degree of polymerization in a range of 150 to 320 with the sulfamic acid. 
     
     
       9. The method of  claim 1 , wherein the treating of cellulose fiber with the sulfamic acid comprises treating the cellulose fiber having an average degree of polymerization in a range of 200 to 300 with the sulfamic acid. 
     
     
       10. The method of  claim 1 , wherein the chemically modified cellulose fiber has an average degree of polymerization of less than 320. 
     
     
       11. The method of  claim 1 , wherein the chemically modified cellulose fiber has an average degree of polymerization of less than 300. 
     
     
       12. The method of  claim 1 , wherein the chemically modified cellulose fiber has an average degree of polymerization of less than 250. 
     
     
       13. The method of  claim 1 , wherein the chemically modified cellulose fiber has an average degree of polymerization in a range of 50 to 350. 
     
     
       14. The method of  claim 1 , wherein the chemically modified cellulose fiber has an average degree of polymerization in a range of 80 to 320. 
     
     
       15. The method of  claim 1 , wherein the chemically modified cellulose fiber has an average degree of polymerization in a range of 100 to 300. 
     
     
       16. The method of  claim 1 , wherein the chemically modified cellulose fiber has an average degree of polymerization in a range of 150 to 250. 
     
     
       17. The method of  claim 1 , wherein the chemically modified cellulose fiber has a cellulose I crystal structure and the substituent substituting some of hydroxyl groups of cellulose in the chemically modified cellulose fiber such that an amount of the substituent is in a range of 0.15 to 2.8 mmol per 1 g of the chemically modified cellulose fiber, and the chemically modified cellulose fiber has an average degree of polymerization of less than 350. 
     
     
       18. The method of  claim 1 , wherein the chemically modified cellulose fiber has a cellulose I crystal structure and the substituent substituting some of hydroxyl groups of cellulose in the chemically modified cellulose fiber such that an amount of the substituent is in a range of 0.2 to 2.5 mmol per 1 g of the chemically modified cellulose fiber, and the chemically modified cellulose fiber has an average degree of polymerization of less than 350. 
     
     
       19. The method of  claim 1 , wherein the chemically modified cellulose fiber has a cellulose I crystal structure and the substituent substituting some of hydroxyl groups of cellulose in the chemically modified cellulose fiber such that an amount of the substituent is in a range of 0.2 to 2.0 mmol per 1 g of the chemically modified cellulose fiber, and the chemically modified cellulose fiber has an average degree of polymerization of less than 350. 
     
     
       20. The method of  claim 1 , wherein the chemically modified cellulose fiber has a cellulose I crystal structure and the substituent substituting some of hydroxyl groups of cellulose in the chemically modified cellulose fiber such that an amount of the substituent is in a range of 0.2 to 1.5 mmol per 1 g of the chemically modified cellulose fiber, and the chemically modified cellulose fiber has an average degree of polymerization of less than 350.